Do a malware check with some malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.
All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender: Home Page:
  http://www.microsoft.com/windows/products/winfamily/defender/default.mspx
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

I have a norton product that does all that.

You have not addressed the issue. This add-on brings up a tab that attempts to get me to update.

The Update contains a Threat name: WS.Reputation.1

Firefox should NOT be directing users to site for updates that contain system threats.

Have you investigated the update and verified the threat?

A guess would be that some type of malware got into your Firefox configuration.
Norton doesn't detect the types of infections the above tools do, that's why I suggested you do that.

The player.exe is indeed malicious and you should do a clean reinstall of Firefox to remove all of your extensions and start anew. Your personal data (bookmarks, history, passwords) will be preserved. Your extensions will not. Please be sure to write down your extensions list somewhere safe so you can restore your Settings.

A clean reinstall means you remove Firefox program files and then reinstall Firefox. Please follow these steps:

Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from http://www.mozilla.org and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
   • Mac: Delete Firefox from the Applications folder.
   • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

More information about reinstalling Firefox can be found here.

WARNING: Do not run Firefox's uninstaller or use a third party remover as part of this process, because that could permanently delete your Firefox data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be recovered unless they have been backed up to an external device!

I am not writing to find out how do deal with malware on my computer.

I asked that you verify that the site in question (associated with FIrefox add ons) leads the user to a file containing a threat.

This is the question! Why does Mozilla FIreFox have an add-on that directs the user to a threat?

You should block this add-on or inform the site that either they should remove the threat or Mozilla will not associate with them. Do you agree?

I DID tell you that it was a threat, and then I told you to do a clean reinstall to get rid of this addon. (see answer-563442)

Quote answer-563442-:
The player.exe is indeed malicious and you should do a clean reinstall of Firefox to remove all of your extensions and start anew. Your personal data (bookmarks, history, passwords) will be preserved. Your extensions will not. Please be sure to write down your extensions list somewhere safe so you can restore your Settings.

You said:

You should block this add-on or inform the site that either they should remove the threat or Mozilla will not associate with them. Do you agree?

The people who answer questions here, for the most part, are other Firefox users volunteering their time (like me), not Mozilla employees or Firefox developers. Therefore we can't do anything about that.

Why does Mozilla FIreFox have an add-on that directs the user to a threat?

By the way, Firefox doesn't install malicious add-ons by itself. The user is in control of what happens with Firefox. There's always a risk of downloading something malicious